Resist pattern thickening material, resist pattern and forming process thereof, and semiconductor device and manufacturing process thereof

ABSTRACT

A resist pattern thickening material has resin, a crosslinking agent and a compound having a cyclic structure, or resin having a cyclic structure at a part. A resist pattern has a surface layer on a resist pattern to be thickened with etching rate (nm/s) ratio of the resist pattern to be thickened the surface layer of 1.1 or more, under the same condition, or a surface layer to a resist pattern to be thickened. A process for forming a resist pattern includes applying the thickening material after forming a resist pattern to be thickened on its surface. A semiconductor device has a pattern formed by the resist pattern. A process for manufacturing the semiconductor device has applying, after forming a resist pattern to be thickened, the thickening material to the surface of the resist pattern to be thickened, and patterning the underlying layer by etching, the pattern as a mask.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 2001-361505, filed onNov. 27, 2001, the prior Japanese Patent Application No. 2002-139317,filed on May 14, 2002 and the prior Japanese Patent Application No.2002-328931, filed on Nov. 12, 2002, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a resist pattern thickeningmaterial which thickens a resist pattern by being applied onto a resistpattern that is formed of an ArF resist, may form a fine patternexceeding exposure limit of optical source of an exposure device, andallows for improving etching resistance of the resist pattern; a resistpattern which may be patterned by an ArF excimer laser and the like, hasa fine structure, and is excellent in etching resistance; and anefficient process for forming the resist pattern; a semiconductor devicehaving a fine pattern formed by the resist pattern, and an efficientprocess for manufacturing the semiconductor device.

[0004] 2. Description of the Related Art

[0005] Recently, a semiconductor integrated circuit is highlyintegrated. LSI and VLSI have been utilized. Accordingly, a wiringpattern now reaches the range of less than 0.2 μm, and the minimumpattern is 0.1 μm or less. In order to form a fine wiring pattern, it isvery important to take advantage of lithography, which refers to thesteps to cover a treating substrate formed of thin films by a resistfilm, to form a resist pattern by developing after selectively exposinglight, and to carry out dry-etching by using the resist pattern as amask. Thereafter, it is also very important to obtain a desired patternby removing the resist pattern.

[0006] In order to form a fine wiring pattern, it is necessary both toshorten a wavelength of optical source of an exposure device, and todevelop a resist material which has a high resolution based uponproperties of an optical source. However, in order to shorten thewavelength of the optical source at the exposure device, it isindispensable to renew an exposure device, which results in considerableexpenses. Developing a resist material which suits an exposure with ashorter wavelength is not very easy.

[0007] A process of manufacturing a semiconductor device includes firstforming a fine pattern by resist pattern, and then finely using theresist pattern as a mask. Therefore, the resist pattern is preferablyexcellent in etching resistance. However, the newest technique, an ArF(argon fluoride) excimer laser exposure, has a problem that a resistpattern used for the exposure is insufficient in etching resistance. Itis possible to use a KrF (krypton fluoride) resist, but the KrF resistsometimes has insufficient etching resistance in a case of a severeetching condition, a thick treating layer, forming a fine pattern, andhaving a thin resist thickness. There has been a request for a techniqueto form a resist pattern excellent in etching resistance, and to form afine pattern by using the resist pattern.

[0008] A technique called RELACS is described in Japanese PatentApplication Laid-Open No. 10-73927, in which a fine pattern can beformed by use of KrF (krypton fluoride) excimer laser (wavelength: 248nm) of deep ultraviolet beam as the exposure light for a resist. Thistechnique comprises forming a resist pattern by exposing the resist(positive type or negative type) with the KrF (krypton fluoride) excimerlaser (wavelength: 248 nm) as the exposure light, providing a film byuse of a water-soluble resin composition so as to cover the resistpattern, making the film interact with the resist pattern in theinterface by use of the residual acid in the material of the resistpattern to thicken (hereinafter often referred also to as “swell”) theresist pattern, thereby shortening the pitch between resist patterns toform the fine pattern.

[0009] In that case, however, the KrF (krypton fluoride) resist is anaromatic resin composition such as novolac resin, naphtoquinodiadido,and the like. Since an aromatic ring contained in the aromatic resincomposition absorbs the ArF excimer laser light, the ArF (argonfluoride) excimer laser light is unable to transmit the KrF resist.Therefore, the ArF (argon fluoride) excimer laser light, which has ashorter wavelength than the ArF excimer laser light, cannot be used asthe exposure light.

[0010] From the viewpoint of forming a fine wiring pattern, it ispreferable that the ArF (argon fluoride) excimer laser light can also beused.

[0011] Accordingly, a technique to form a fine pattern excellent inetching resistance with low cost, by using the ArF (argon fluoride)excimer laser light as an optical source of an exposure device whenpatterning is not yet provided.

SUMMARY OF THE INVENTION

[0012] An object of the present invention is to provide a resist patternthickening material capable of forming a fine pattern with low cost byapplying the resist pattern thickening material, exceeding an exposurelimit for an optical resource of an exposure device, improving theetching resistance of the resist pattern.

[0013] The present invention has a further object to provide a resistpattern which can be patterned by using ArF excimer laser, has a finestructure, and is excellent in etching resistance.

[0014] Another object of the present invention is to provide a processfor forming a resist pattern capable of using ArF excimer laser light asexposure light with excellent mass-productivity and forming a finepattern by the resist pattern over the exposure limit of light with lowcost, with ease, and with improving etching resistance.

[0015] The present invention has an additional object to provide ahigh-performance semiconductor device having a fine pattern formed by aresist pattern.

[0016] The present invention has another object to provide a process formanufacturing a semiconductor device capable of using ArF excimer laser,an exposure light, and efficiently mass-producing a high-performancesemiconductor device having a fine pattern by a resist pattern finelyformed thereon exceeding the exposure limit of light.

[0017] The resist pattern thickening material of the present inventioncomprises a resin, a crosslinking agent and a compound having a cyclicstructure, or it comprises a resin which has a cyclic structure at apart and a crosslinking agent.

[0018] When the resist pattern thickening material is applied onto aresist pattern, among the applied resist pattern thickening material, aportion thereof present near the interface with the resist pattern ispenetrated into the resist pattern and then crosslinked with (mixedwith) the material of the resist pattern. The resist pattern thickeningmaterial shows good affinity toward the resist pattern. Therefore, asurface layer (a mixing layer), where the resist pattern thickeningmaterial is integrated (mixed) into the resist pattern, is efficientlyformed on a surface of the resist pattern (the resist pattern isefficiently thickened by the resist pattern thickening material).

[0019] Since the surface layer is formed of the resist patternthickening material and contains the compound having a cyclic structureor a resin which has a cyclic structure at least at a part, the surfacelayer in the resist pattern is excellent in etching resistance. As aresult of that the resist pattern formed (hereinafter, referred to as a“resist pattern”) is already thickened by the resist pattern thickeningmaterial, the pattern formed by the resist pattern has a finerstructure, exceeding an exposure limit.

[0020] The resist pattern of the present invention comprises a surfacelayer on a resist pattern to be thickened, with a ratio of 1.1 or more(resist pattern to be thickened to surface layer) in etching rate (nm/s)of the surface layer to the resist pattern under the same condition. Theresist pattern can be formed by using an ArF excimer laser for anexposure light. Since this resist pattern has the highlyetching-resistant surface layer, it is suitable for etching process, andfor forming of a fine pattern.

[0021] The process for forming a resist pattern of the present inventioncomprises a step for applying the resist pattern thickening material ofthe present invention so as to cover a surface of a resist pattern to bethickened after a step of formation of the resist pattern to bethickened. When the resist pattern thickening material is applied onto aresist pattern to be thickened, in the coated resist pattern thickeningmaterial, a portion thereof present near the interface with the resistpattern is penetrated into the resist pattern to be thickened and thencrosslinked with (mixed with) the material of the resist pattern.Therefore, the resist pattern thickening material is integrated into theresist pattern to be thickened (a mixing layer is formed). The surfacelayer is formed of the resist pattern thickening material, and comprisesa compound having a cyclic structure or a resin which has a cyclicstructure at least at a part, hence the surface layer is excellent inetching resistance. The resist pattern thus formed is already thickenedby the resist pattern thickening material. Therefore, a pattern formedby the resist pattern has a finer structure, exceeding an exposurelimit.

[0022] The semiconductor device of the present invention comprises apattern formed by the resist pattern of the present invention.

[0023] This semiconductor device has a high quality and high performancesince it has a fine pattern formed by this resist pattern.

[0024] The process for manufacturing a semiconductor device of thepresent invention comprises a step for forming a resist pattern byapplying the resist pattern thickening material of the present inventionto cover a surface of a resist pattern to be thickened to thicken theresist pattern to be thickened to form the resist pattern, after formingthe resist pattern to be thickened on an underlying layer, and a stepfor patterning the underlying layer by performing an etching using theresist pattern formed in the step for forming the resist pattern as amask.

[0025] In this process for manufacturing a semiconductor device, theresist pattern thickening material is applied onto the resist pattern tobe thickened after the resist pattern to be thickened is formed on theunderlying layer. The resist pattern thickening material present nearthe interface with the resist pattern to be thickened is penetrated intothe resist pattern to be thickened and then crosslinked with thematerial of the resist pattern. Therefore, a surface layer integratedwith the resist pattern to be thickened is formed on the resist patternto be thickened. Since the surface layer (mixing layer) is formed of theresist pattern thickening material and contains the compound having acyclic structure and the resin which has a cyclic structure at least ata part, the surface layer in the resulting resist pattern is excellentin etching resistance, and the etching processing or the like can besuitably performed. Since the resulting resist pattern is thickened bythe resist pattern thickening material, the pitch of the pattern by theresist pattern is smaller (finer) than the pitch formed by the resistpattern prior to thickening, to the extent of the thickened portion bythe resist pattern thickening material. The finer pattern by the resistpattern is formed exceeding the exposure limit of light.

[0026] By etching over the mask of the resist pattern which hasexcellent etching resistance, the resist to be thickened is finelypatterned.

[0027] As a result, a semiconductor device having an extremely finepattern can be efficiently manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028]FIGS. 1A through 1C is a schematic view for showing a mechanism ofthickening of a resist pattern by use of a resist pattern thickeningmaterial according to the present invention.

[0029]FIGS. 2A through 2E are schematic views for showing one example ofa process for forming a resist pattern according to the presentinvention.

[0030]FIGS. 3A and 3B are upper surface views of a FLASH EPROM that isone example of a semiconductor device according to the presentinvention.

[0031]FIGS. 4A through 4C are schematic sectional views (1) for showinga manufacturing process for FLASH EPROM that is one example of a processfor manufacturing a semiconductor device according to the presentinvention.

[0032]FIGS. 5D through 5F are schematic sectional views (2) for showinga manufacturing process for FLASH EPROM that is one example of a processfor manufacturing a semiconductor device according to the presentinvention.

[0033]FIGS. 6G through 6I are schematic sectional views (3) for showinga manufacturing process for FLASH EPROM that is one example of a processfor manufacturing a semiconductor device according to the presentinvention.

[0034]FIGS. 7A through 7C are schematic sectional views for showing amanufacturing process for FLASH EPROM that is another embodiment of theprocess for manufacturing a semiconductor device according to thepresent invention.

[0035]FIGS. 8A through 8C are schematic sectional views for showing amanufacturing process for FLASH EPROM that is another embodiment of theprocess for manufacturing a semiconductor device according to thepresent invention.

[0036]FIGS. 9A through 9D are schematic sectional views for showing oneexample of the application of a resist pattern thickened by use of theresist pattern thickening material of the present invention tomanufacture of a magnetic head.

[0037]FIG. 10 is a schematic sectional view for showing a process (1) ofone example of the application of the resist pattern thickened by use ofthe resist pattern thickening material of the present invention tomanufacture of a magnetic head.

[0038]FIG. 11 is a schematic sectional view for showing a process (2) ofone example of the application of the resist pattern thickened by use ofthe resist pattern thickening material of the present invention tomanufacture of a magnetic head.

[0039]FIG. 12 is a schematic sectional view for showing a process (3) ofone example of the application of the resist pattern thickened by use ofthe resist pattern thickening material of the present invention tomanufacture of a magnetic head.

[0040]FIG. 13 is a schematic sectional view for showing a process (4) ofanother example of the application of the resist pattern thickened byuse of the resist pattern thickening material of the present inventionto manufacture of a magnetic head.

[0041]FIG. 14 is a schematic sectional view for showing a process (5) ofanother example of the application of the resist pattern thickened byuse of the resist pattern thickening material of the present inventionto manufacture of a magnetic head.

[0042]FIG. 15 is a schematic sectional view for showing a process (6) ofanother example of the application of the resist pattern thickened byuse of the resist pattern thickening material of the present inventionto manufacture of a magnetic head.

[0043]FIG. 16 is a plan view showing one example of the magnetic headmanufactured in the processes of FIGS. 10 to 15

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] (Resist Pattern Thickening Material)

[0045] The resist pattern thickening material of the present inventionis a water-soluble or an alkali-soluble composition, which is suitablyin aqueous solution. The compositions may be in colloidal solution,emulsion solution, and the like.

[0046] The preferable examples for the resist pattern thickeningmaterial of the present invention include the first and the secondembodiments.

[0047] The resist pattern thickening material of the first embodimentcontains a resin, a crosslinking agent, and a compound having a cyclicstructure, and further contains a surfactant, an organic solvent, andother components according to the purpose. The resin may have a cyclicstructure at a part of itself.

[0048] The resist pattern thickening material of the second embodimentcontains a crosslinking agent and a resin which has a cyclic structureat one part. The resist pattern thickening material further contains theresin, the compound having a cyclic structure, the non-ionic surfactant,the organic solvent, and the other compositions.

[0049] Resin

[0050] The resin is not particularly limited, and can be properlyselected according to purposes. However, the preferable example includesa water-soluble resin, or an alkali-soluble resin. The more preferableexamples include a resin that can cause cross-linking reaction, or aresin that can be mixed with a crosslinking agent. Those resins may beused either alone or in combination of two or more.

[0051] When the resin is a water-soluble resin, the resin preferablyexhibits a water-solubility of 0.1 g or more to 25° C. water, morepreferably 0.3 g or more to water, and particularly more preferably 0.5g or more to water.

[0052] Examples of the water-soluble resins include polyvinyl alcohol,polyvinyl acetal, polyvinyl acetate, polyacrylic acid, polyvinylpyrrolidone, polyethylene imine, polyethylene oxide, styrene-maleic acidcopolymer, polyvinyl amine, polyarylamine, oxazoline group-containingwater-soluble resin, water-soluble melamine resin, water-soluble urearesin, alkyd resin, sulfonamide resin, and the like.

[0053] When the resin is an alkali-soluble, the alkali-soluble resinpreferably exhibits an alkali-solubility of 0.1 g or more to 25° C.2.38% by mass tetramethylammoniumhydroxide (TMAH) aqueous solution, morepreferably, the 0.3 g or more to the TMAH solution, and particularlypreferably 0.5 g or more to the TMAH solution.

[0054] Examples of the alkali-soluble resin include a novolac resin, avinylphenyl resin, polyacryl acid, polymethaacryl acid, polyp-hydroxyphenylacrylate, poly p-hydroxyphenylmethacrylate, copolymersthereof, and the like.

[0055] Of these, the polyvinyl alcohol, polyvinyl acetal and polyvinylacetate are preferably used. In the present invention, the resinpreferably contains the polyvinyl acetal, and more preferably contains5% by mass to 40% by mass of the polyvinyl acetal because the solubilityis easily changeable by crosslinking.

[0056] In the present invention, in a case of the resist patternthickening material relating to the first embodiment, the resin maycontain a cyclic structure at a part. The resist pattern thickeningmaterial relating to the second embodiment consists essentially of aresin which has the cyclic structure at a part of the resin, and mayfurther contain the resin. Examples of the cyclic structure are notparticularly limited, and are preferably selected according to thepurpose. The examples may be selected from an aromatic compound, analicyclic compound, and a heterocyclic compound.

[0057] Examples of the an aromatic compound include a multivalent phenolcompound, a polyphenol compound, an aromatic polyphenol compound, anaromatic carboxylic acid compound, a perhydroxy naphthalene compound, abenzophenone compound, a flavonoid compound, a porphine, a water-solublephenoxy resin, an aromatic-containing water-soluble pigment, derivativesand glycosides thereof, and the like. These may be used either alone orin combination of two or more.

[0058] Examples of the multivalent phenol compound include resorcin,resorcin[4]arene, pyrogallol, gallic acid, derivatives and glycosidesthereof, and the like.

[0059] Examples of the polyphenol compound and derivatives thereofinclude catechin, anthocyanidin (pelargonidine type (4′-hydroxy),cyanidin type (3′,4′-dihydroxy), delphinidin type (3′,4′,5′-trihydroxy),flavane-3,4-diol, proantocyanidin, derivatives and glycosides thereof,and the like.

[0060] Examples of the aromatic carboxylic acid compound and derivativesthereof include salicylic acid, phthalic acid, dihydroxybenzoic acid,tannin, derivatives and glycosides thereof, and the like.

[0061] Examples of the perhydroxy naphthalene compound and derivativesthereof include naphthalene diol, naphthalene triol, derivatives andglycosides thereof, and the like.

[0062] Examples of the benzophenone compound and derivative thereofinclude alizarin yellow A, derivatives and glycosides thereof, and thelike.

[0063] Examples of the flavonoid compound and derivatives thereofinclude flavone, isoflavone, flavanol, flavonone, flavonol, flavan-3-ol,aurone, chalcone, dihydrochalcone, quercetin, derivatives or glycosidesthereof, and the like.

[0064] Examples of the alicyclic compound include polycycloalkane,cycloalkane, a condensed ring, derivatives and glycosides thereof, andthe like. These may be used either alone or in combination of two ormore.

[0065] Example of the polycycloalkane include norbornane, adamantane,norpinane, sterane, and the like.

[0066] Examples of the cycloalkane include cyclopentane, cyclohexane,and the like.

[0067] Examples of the condensed ring include steroid, and the like.

[0068] Suitable examples of the heterocyclic compound include a nitrogencontained cyclic compound such as pyrrolidine, pyridine, imidazole,oxazole, morphorine, pyrrolidone, and the like; a oxygen containedcyclic compound such as furan, pyran, polysaccharide including, pentose,hexose, and the like.

[0069] Among the resins and the resins which has a cyclic structure at apart, a preferable resin or a resin which has a cyclic structure at parthas two or more of polar groups, from the view points that the resin isexcellent in at least either a water-solubility or an alkali-solubility.

[0070] Examples of the polar groups are not particularly limited, andcan be selected according to purposes. Suitable examples include ahydroxy group, a cyano group, an alkoxyl group, a carboxyl group, acarbonyl group, an amino group, an amide group, an alkoxycarbonyl group,a hydroxyalkyl group, a sulfonyl group, an hydride group, a lactonegroup, a cyanate group, an isocyanate group, a ketone group, and thelike. Of those polar groups, more suitable examples include a hydroxygroup, a carboxyl group, a carbonyl group, an amino group, a sulfonylgroup, and the like.

[0071] When the resin has the compound having a cyclic structure at apart, the rest of the part of the cyclic structure can be selectedaccording to the purpose, as long as it may be either water-soluble oralkali-soluble. Examples include a water-soluble resin such as polyvinylalcohol, polyviniylacetal, and the like; an alkali resin such as novolacresin, a vinylphenyl resin and the like.

[0072] When the resin has the cyclic structure at a part of it, a molcontent of the cyclic structure is not particularly limited and can beselected from according to purpose. If the resin requires high etchingresistance, the mol content is preferable 5 mol % or more, morepreferably, 10 mol % or more.

[0073] The mol content can be measured by using, for example, NMR, andthe like.

[0074] The content of the resin in the resist pattern thickeningmaterial may be properly determined according to the purpose. Althoughit varies depending on the type, the content of the crosslinking agent,the compound having a cyclic structure, and the surfactant can beselected according to the purpose.

[0075] Crosslinking Agent

[0076] The crosslinking agent is not particularly limited, and any onecan be properly selected according to purposes. A water-soluble or analkali-soluble crosslinking agent is preferred. Those cross-linkable byheat or acid is also preferable. Suitable examples include an amino typecrosslinking agent and the like.

[0077] Suitable examples of the amino type crosslinking agent include amelamine derivative, a urea derivative, an uril derivative and the like.These may be used individually or in combination.

[0078] Examples of the urea derivative include urea, alkoxy methyleneurea, N-alkoxy methylene urea, ethylene urea, ethylene urea carboxylicacid, derivatives thereof, and the like.

[0079] Examples of the melamine derivative include alkoxymethylmelamine, derivatives thereof, and the like.

[0080] Examples of the uril derivative include benzoguanamine,glycouril, derivatives thereof, and the like.

[0081] The content of the crosslinking agent in the resist patternthickening material may be properly determined according to purposesalthough it varies depending on the type, content and the like, theresin which has the compound having a cyclic structure and thesurfactant cannot be indiscriminately regulated.

[0082] Compound Having a Cyclic Structure

[0083] Examples of the compound having a cyclic structure may be eithera compound or a resin. More preferably, those resins or compounds may beeither water-soluble or alkali-soluble. Since the resist patternthickening material of the present invention contains the compoundhaving a cyclic structure, it is possible to remarkably improve theetching resistance of the resist pattern.

[0084] If the compound having a cyclic structure is water-soluble, thepreferable water-solubility is 0.1 g or more to 100 g of 25° C. water,more preferably 0.3 g or more to 100 g of 25° C. water, and particularlypreferably 0.5 g or more to 100 g of 25° C. water.

[0085] When the compound having a cyclic structure is alkali-soluble,the preferable alkali-solubility is 0.1 g or more to 25° C. of 2.38%TMAH solution, more preferably 0.3 g or more to 25° C. of the 2.38% TMAHsolution, and particularly preferably 0.5 g or more to 25° C. of 2.38%the TMAH solution.

[0086] Examples of the compound having a cyclic structure include thearomatic compound, the alicyclic compound, the heterocyclic compound,and the like. The specific examples for those compounds are shown in theabove.

[0087] Of those compounds having a cyclic structure, the compound havinga cyclic structure has preferably 2 or more of polar groups, morepreferably 3 or more of polar groups, and particularly preferably 4 ormore of polar groups, from the viewpoint that the compound is excellenteither in water-solubility or in alkali-solubility.

[0088] The polar group is not particularly limited, and any polar groupcan be properly selected according to purposes, including a hydroxylgroup, a cyano group, an alkoxy group, a carboxyl group, a carbonylgroup, an amino group, an amide group, an alkoxycarbonyl group, ahydroxyalkyl group, a sulfonyl group, a hydride group, a lactone group,a cyanate group, an isocyanate group, a ketone group, and the like. Ofthese, the suitable examples include a hydroxyl group, a carboxyl group,a carbonyl group, an amino group, and a sulfonyl group.

[0089] When the compound having a cyclic structure is a resin, a molcontent of the compound having a cyclic structure to the resin is notparticularly limited, and can be suitably selected according to thepurposes. If the resin requires high etching resistance, the content ispreferably 5 mol % or more, more preferably 10 mol % or more. The molcontent can be measured by NMR and the like.

[0090] The content of the a compound having a cyclic structure in theresist pattern thickening material may be properly determined accordingto the types and the content of the resin, the crosslinking agent, thesurfactant, and the like.

[0091] Surfactant

[0092] The surfactant can be suitably used when the affinity of theresist pattern thickening material with the resist pattern (forinstance, an ArF resist pattern) to be applied to the resist patternthickening material is insufficient. When the surfactant is contained inthe resist pattern thickening material, the resist pattern can beefficiently thickened in the state excellent in in-plane uniformity toefficiently and uniformly form a fine pattern, and the foaming of theresist pattern thickening material can be also effectively suppressed.

[0093] The surfactant is not particularly limited, and any one can beproperly selected according to purposes, including a non-ionicsurfactant, a cationic surfactant, an anionic surfactant, an ampholyticsurfactant, a silicone type surfactant and the like. These can be usedeither alone or in combination of two or more. Of these, the non-ionicsurfactant is preferable because it has a structure containing no metalion.

[0094] The non-ionic surfactant is not particularly limited, and can beselected according to the purposes. A specific example of the non-ionicsurfactant is selected from an alkoxylate surfactant, a fatty acid estersurfactant, an amide surfactant, an alcohol surfactant, and anethylenediamine surfactant. The specific examples of those surfactantsinclude a polyoxyethylene-polyoxypropylene condensed compound, apolyoxyalkylene alkyl ether compound, a polyoxyethylene alkyl ethercompound, a polyoxyethylene derivative compound, a sorbitan fatty acidester compound, a glycerin fatty acid ester compound, a primary alcoholethoxylate compound, a phenol ethoxylate compound, anonylphenolethoxylate type, an octylphenolethoxylate type, a laurylalcohol ethoxylate type, an oleyl alcohol ethoxylate type, a fatty acidtype, an amide type, a natural alcohol type, an ethylenediamine type, asecondary alcoholethoxylate type, and the like.

[0095] The cationic surfactant is not particularly limited, and can beselected according to the purposes. The examples include analkylcationic surfactant, an amide type quaternary cationic surfactant,ester type quaternary cationic surfactant, and the like.

[0096] The ampholytic surfactant is not particularly limited and can beselected according to the purposes. The examples include an amine oxidesurfactant, a betaine surfactant, and the like.

[0097] The content of the surfactant in the resist pattern thickeningmaterial may be properly determined according to purposes, although itvaries depending on the type, content, and the like of the above resin,crosslinking agent, compound having a cyclic structure and the like andcannot be indiscriminately regulated.

[0098] Organic Solvent

[0099] The organic solvent can improve the solubility of the aboveresin, crosslinking agent, the compound having a cyclic structure, andthe resin which has the cyclic structure at a part in the resist patternthickening material by being included in the resist pattern thickeningmaterial.

[0100] The organic solvent is not particularly limited, and any one canbe properly selected according to purposes, including an alcoholicorganic solvent, a chain ester organic solvent, a cyclic ester organicsolvent, a ketone organic solvent, a chain ether organic solvent, acyclic ether organic solvent and the like.

[0101] Examples of the alcoholic organic solvent include methanol,ethanol, propyl alcohol, isopropyl alcohol, butyl alcohol, and the like.

[0102] Examples of the chain ester organic solvent include ethyllactate, propylene glycol methyl ether acetate (PGMEA), etc.

[0103] Examples of the cyclic ester organic solvent include a lactonetype such as γ-butyrolactone, etc.

[0104] Examples of the ketone organic solvent include a ketone type suchas acetone, cyclohexanone, heptanone, etc.

[0105] Examples of the chain ether organic solvent include ethyleneglycol dimethyl ether, etc.

[0106] Examples of the cyclic ether include tetrahydrofuran, dioxane,etc.

[0107] These organic solvents may be used individually or incombination. Of these, a one having a boiling point of about 80° C. to200° C. is preferably used because the thickening can be finelyperformed.

[0108] The content of the organic solvent in the resist patternthickening material may be properly determined according to purposesalthough it is varied depending on the kind, content and the like of theabove resin, crosslinking agent, the compound having a cyclic structure,and surfactant and cannot be indiscriminately regulated.

[0109] Other Components

[0110] Other components are not particularly limited as long as they donot impair the effect of the present invention, and any one can beproperly selected according to purposes, including known additives ofall types. The suitable examples include a thermal acid generator, aquencher represented by amine type, amide type, ammonium salt, and thelike.

[0111] The content of the other components in the resist patternthickening material may be properly determined according to purposesalthough it is varied depending on the kind, content and the like of theabove resin, crosslinking agent, the compound having a cyclic structure,surfactant, organic solvent and the like and cannot be indiscriminatelyregulated.

[0112] Use or the Like

[0113] The resist pattern thickening material of the present inventioncan be used by applying onto the resist pattern.

[0114] During applying, the surfactant may be separately applied priorto the application of the resist pattern thickening material withoutbeing included in the resist pattern thickening material.

[0115] When the resist pattern thickening material is applied onto theresist pattern to be thickened, the resist pattern is thickened and thusthe resist pattern is formed.

[0116] The pattern thus formed by thickening resist pattern has ashorter diameter of a hole pattern and a shorter pitch of a line & spaceresist pattern than those of the patterns formed by the aforementionedresist patterns. Applying the resist pattern thickening material allowsa pattern to form a finer pattern, exceeding the exposure limit of anexposure device used for patterning the resist pattern. For example,when an ArF excimer laser is used, an obtained resist pattern isthickened by the resist pattern thickening material of the presentinvention, and then a resist pattern is formed. In doing so, a patternformed by the resist pattern has as fine pattern as the one patterned byan electron beam.

[0117] Thickened parts of the resist pattern can be controlled to adesired range, according to a viscosity, a thickness of the appliedmaterial, a baking temperature, a baking time, and the like of theresist pattern thickening material.

[0118] Material for Resist Pattern (Resist Pattern to be Thickened)

[0119] The material for the resist pattern (resist pattern to bethickened) is not particularly limited, and any one can be properlyselected from known resist materials according to purposes, which may beof negative type and positive type, including a chemically amplifiedresist material represented by a g-line resist, an I-line resist, a KrFresist, an ArF resist, an F2 resist, an electron beam resist, and thelike, all of which can be patterned by g-line, I-line, a KrF excimerlaser, an ArF excimer laser, an F2 excimer laser, an electron beam, andthe like. Those may be either a chemical amplification type or anon-chemical amplification type. Of these, a KrF resist, an ArF resist,and the like are preferred. An ArF resist is more preferred.

[0120] Examples of the resist pattern material include a novolac resist,a PHS resist, an acryl resist, a cycloolefin-maleic anhydride (COMAtype) resist, a cycloolefin resist, a hybrid (alicyclic acrylate-COMAcopolymer) resist, and the like. Those resists may be fluorine-modified.

[0121] The forming process, size, thickness and the like of the resistpattern are not particularly limited, and any one can be properlyselected according to purposes. Particularly, the thickness is generallyset to about 0.2 μm to 200 μm although it can be properly determineddepending on the underlying layer to be worked, etching conditions andthe like.

[0122] The thickening of the resist pattern to be thickened using theresist pattern thickening material of the present invention is describedbelow in reference to the drawings.

[0123] As shown in FIG. 1A, a resist pattern (resist pattern to bethickened) 3 is formed on a substrate (base material) 5, and a resistpattern thickening material 1 is then applied to the surface of theresist pattern (the resist pattern to be thickened) 3 and pre-baked(heated and dried) to form a film. The mixing (penetration) of theresist pattern thickening material 1 into the resist pattern to bethickened 3 then occurs near the interface between the resist pattern tobe thickened 3 and the resist pattern thickening material 1. The mixing(penetration) part is crosslinked, hence a mixing layer comprising theresist pattern to be thickened 3 and the resist pattern thickeningmaterial 1. As shown in FIG. 1B, a resist pattern comprises a surfacelayer 10 a, which is the mixing layer, on a resist pattern to bethickened 10 b (resist pattern to be thickened 3).

[0124] Thereafter, a developing processing is performed as shown in FIG.1C, whereby the part which is not mixed with the resist pattern to bethickened 3 of the applied resist pattern thickening material 1 isdissolved and removed to form (develop) a resist pattern 10.

[0125] The step for developing may be water development or a developmentwith alkali developer.

[0126] The resist pattern 10 comprises a surface layer 10 a formed bymixing (penetrating) and crosslinking the resist pattern thickeningmaterial 1 on the surface of a resist pattern to be thickened 10 b.Since the a resist pattern 10 is thickened to the extend of thicknessportion of the surface layer 10 a, compared with the resist pattern(resist pattern to be thickened) 3, the pitch of the pattern formed bythe resist pattern 10 is shorter than that of the pattern formed by theresist pattern 3, and the pattern formed by the resist pattern 10 isfine. This allows for forming a finer pattern exceeding an exposurelimit of an optical source of an exposure device. A pattern formed bythe resist pattern 10 is finer than a pattern formed by the resistpattern 3.

[0127] The surface layer 10 a in the resist pattern 10 is formed of theresist pattern thickening material 1 which comprises either the compoundhaving a cyclic structure or the resin which has the cyclic structure ata part, hence the resist pattern thickening material 1 is remarkablyexcellent in etching resistance. Therefore, even if the resist patternto be thickened 3 is formed of a material inferior in etchingresistance, the resist pattern 10 having the surface layer 10 aexcellent in etching resistance on the surface is thus remarkablyexcellent in etching resistance.

[0128] Use

[0129] The resist pattern thickening material of the present inventioncan be suitably used for thickening a resist pattern, and fining apattern, exceeding an exposure limit. The resist pattern thickeningmaterial can be further suitably used for the thickening of the resistpattern to be thickened, and particularly suitably used for the resistpattern and forming process thereof of the present invention and thesemiconductor device and manufacturing process thereof of the presentinvention.

[0130] The resist pattern thickening material of the present inventioncontains either the compound having a cyclic structure or the resinwhich has the cyclic structure at a part. Therefore, the resist patternthickening material is suitable for prasma, and the like, is alsosuitable for applying and thickening a pattern formed of a resin thatrequires an improvement of etching resistance of a surface. The resistpattern thickening material can be more suitably used especially whenthe material for the resist pattern to be thickened does not include thecompound having a cyclic structure or the resin which has the cyclicstructure at a part.

[0131] (Resist Pattern)

[0132] The resist pattern of the present invention comprises a surfacelayer on a resist pattern to be thickened.

[0133] The surface layer is preferably excellent in etching resistance,and its etching rate (nm/s) is preferably small, compared with theresist pattern to be thickened. Concretely, the ratio (resistpattern/surface layer) in etching rate (nm/s) of the resist pattern tobe thickened to the surface layer is preferably 1.1 more preferably 1.2or more, and particularly preferably 1.3 or more.

[0134] The etching rate (nm/s) can be measured, for example, byperforming an etching processing for a prescribed time by use of a knownetching device to measure the film reducing amount of a sample andcalculating the film reducing amount per unit time.

[0135] The surface layer preferably contains the compound having acyclic structure or the resin which has a cyclic structure at least at apart, and can be suitably formed by use of the resist pattern thickeningmaterial of the present invention.

[0136] Whether or not the surface layer contains the compound having acyclic structure or the resin which has a cyclic structure at least at apart can be confirmed, for example, by analyzing the IR or UV absorptionspectrum for this surface layer.

[0137] The resist pattern may contain at least one of the compoundhaving a cyclic structure and the resin which has a cyclic structure atleast at a part. This embodiment is also preferred from the viewpoint ofconverting a resist pattern to be thickened.

[0138] The resist pattern of the present invention may have a structurehaving a clear boundary between the resist pattern to be thickened andthe surface layer or an unclear boundary. In the former structure, thecontent of the compound having a cyclic structure and the resin whichhas a cyclic structure at least at a part is generally discontinuouslyreduced from the surface layer to the inner part, and in the latterstructure, the content of the compound having a cyclic structure and theresin which has a cyclic structure at least at a part is generallygradually reduced from the surface layer to the inner part.

[0139] The resist pattern of the present invention can be suitablymanufactured according to the process for forming the resist pattern ofthe present invention described below.

[0140] The resist pattern of the present invention can be suitably usedfor a functional part such as mask pattern, reticle pattern, magnetichead, LCD (liquid crystal display), PDP (plasma display panel), SAWfilter (surface acoustic wave filter), and the like; an optical partused for connection of optical wiring; a micro part such as microactuator, and the like; a semiconductor device and the like, andsuitably used for the semiconductor device of the present inventiondescribed later.

[0141] (Process for Forming a Resist Pattern)

[0142] The process for forming the resist pattern of the presentinvention comprises a step for applying a resist pattern thickeningmaterial so as to cover a surface of a resist pattern to be thickenedafter formation of the resist pattern to be thickened.

[0143] The materials for the resist pattern to be thickened includethose described above for the resist pattern thickening material of thepresent invention. One of the preferable examples is an ArF resist.

[0144] The resist pattern to be thickened can be formed according to aknown process.

[0145] The resist pattern to be thickened can be formed of an underlyinglayer (base material). The underlying layer (base material) is notparticularly limited, and any one can be properly selected according topurposes. When the resist pattern to be thickened is ordinarily formedon a semiconductor device, the examples of substrate include silicon,various oxide films, and the like.

[0146] The application process for the resist pattern thickeningmaterial is not particularly limited, and any process can be properlyselected from known application processes according to purposes,suitably including spin coating and the like. The condition for the spincoating, for example, the cycle is set to about 100 rpm to 10000 rpm,preferably 800 rpm to 5000 rpm, and the coating time is set to about 1second to 10 minutes, preferably 1 second to 90 seconds.

[0147] The thickness of the applied material during the application isordinarily around 10 nm to 1000 nm (100 Å to 10000 Å), more preferably50 nm to 500 nm (500 Å to 5000 Å).

[0148] In applying, the surfactant may be separately applied prior tothe application of the resist pattern thickening material without beingincluded in the resist pattern thickening material.

[0149] The applied resist pattern thickening material is preferablypre-baked (heated and dried) in or after the application because themixing (penetration) of the resist pattern thickening material into theresist pattern to be thickened can be efficiently caused in theinterface between the resist pattern to be thickened and the resistpattern thickening material.

[0150] The condition, process and the like of the pre-baking (heatingand drying) are not particularly limited as long as a resist pattern isnot softened, and any one can be properly selected according topurposes. For example, the temperature is set to about 40° C. to 120°C., preferably 70° C. to 100° C., and the time is set to about 10seconds to 5 minutes, preferably 40 seconds to 100 seconds.

[0151] The crosslinking baking (crosslinking reaction) of the appliedresist pattern thickening material is preferably performed after thepre-baking (heating and drying) because the crosslinking reaction of themixed (penetrated) part can be efficiently progressed in the interfacebetween the resist pattern to be thickened and the resist patternthickening material.

[0152] The condition, process and the like of the crosslinking baking(crosslinking reaction) are not particularly limited, and any one can beproperly selected according to purposes. Generally, a temperaturecondition higher than the pre-baking (heating and drying) is adapted.For the condition of the crosslinking baking (crosslinking reaction),for example, the temperature is set to about 70° C. to 150° C.,preferably 90° C. to 130° C., and the time is set to about 10 seconds to5 minutes, preferably 40 seconds to 100 seconds.

[0153] The step for developing the applied resist pattern thickeningmaterial is preferably performed after the crosslinking baking(crosslinking reaction). In this case, the part not crosslinked with theresist pattern to be thickened and the part weakly crosslinked (mixed)therewith (highly water-soluble part) of the applied resist patternthickening material can be dissolved and removed to develop (to obtain)the resist pattern of the present invention manufactured in thethickened state.

[0154] The step for developing is the same as described above.

[0155] The process for forming the resist pattern of the presentinvention is then described below in reference to the drawings.

[0156] A resist material 3 a is applied onto a substrate (base material)5 as shown in FIG. 2A and then patterned as shown in FIG. 2B to form aresist pattern (resist pattern to be thickened) 3. A resist patternthickening material 1 is applied onto the surface of the resist patternto be thickened 3, and pre-baked (heated and dried) to form a paintfilm. The mixing (penetration) of the resist pattern thickening material1 into the resist pattern (resist pattern to be thickened) 3 occurs inthe interface between the resist pattern (resist pattern to bethickened) 3 and the resist pattern thickening material 1.

[0157] When a crosslinking baking (crosslinking reaction) is preformedat a temperature higher than in the pre-baking (heating and drying) asshown in FIG. 2D, the mixed (penetrated) layer is crosslinked in theinterface between the resist pattern to be thickened 3 and the resistpattern thickening material 1. Thereafter, a step for developing isperformed as shown in FIG. 2E, whereby the part not mixed with theresist pattern (resist pattern to be thickened) 3 and the part weaklycrosslinked therewith (highly water-soluble part) of the applied resistpattern thickening material 1 is dissolved and removed to form (develop)a resist pattern 10 having a surface layer 10 a on a resist pattern tobe thickened 10 b (the resist pattern to be thickened 3).

[0158] The step for developing may be water development or a developmentwith an alkali aqueous solution. The water development is preferablebecause the step for developing can be efficiently performed at a lowcost.

[0159] The resist pattern 10 comprises the surface layer 10 a formed bymixing the resist pattern thickening material 1 onto the resist patternto be thickened 3 on the surface of the resist pattern to be thickened10 b (the resist pattern to be thickened 3). Since the resist pattern 10is thickened by the thickness portion of the surface layer 10 a,compared with the resist pattern to be thickened 3(resist pattern 10 b),the pitch of the pattern formed by the resist pattern 10 is smaller thanthat of the pattern formed by the resist pattern to be thickened 3 (theinterlayer resist pattern 10 b), and a pattern formed by the resistpattern 10 is fine.

[0160] The surface layer 10 a in the resist pattern 10 is formed of theresist pattern thickening material 1. The resist pattern thickeningmaterial 1 is excellent in etching resistance since it contains one ofthe compound having a cyclic structure and the resin which has thecyclic structure. Therefore, even if the resist pattern to be thickened3(interlayer resist pattern 10 b) is formed of a material inferior inetching material, the resist pattern 10 having the surface layer 10 aexcellent in etching resistance can be formed.

[0161] The resist pattern 10 may have a either clear or unclear borderbetween the interlayer resist pattern 10 b and the surface layer 10 a.

[0162] The resist pattern formed according to the process for formingthe resist pattern of the present invention is the resist pattern of thepresent invention. This resist pattern comprises the surface layerformed by mixing the resist pattern thickening material of the presentinvention onto the resist pattern to be thickened on the surface of theresist pattern to be thickened. Therefore, even if the resist pattern tobe thickened is formed of a material inferior in etching resistance, theresist pattern having the surface layer excellent in etching resistanceon the surface of the resist pattern to be thickened can be efficientlyformed according to the forming process for a resist pattern of thepresent invention, because the resist pattern thickening materialcontains at least one of the compound having a cyclic structure and theresin which has the cyclic structure at a part. The resist patternformed according to the forming process for resist pattern of thepresent invention is thickened by the thickness portion of the surfacelayer, compared with the resist pattern to be thickened, the pitch ofthe pattern formed by the manufactured resist pattern is smaller thanthat of the pattern formed by the resist pattern to be thickened priorto thickening. According to the forming process for a resist pattern ofthe present invention, a fine pattern can be thus efficientlymanufactured.

[0163] The resist pattern formed according to the forming process for aresist pattern of the present invention can be suitably used for afunctional part such as mask pattern, reticle pattern, magnetic head,LCD (liquid crystal display), PDP (plasma display panel), SAW filter(surface acoustic wave filter), and the like; an optical part used forconnection of wiring by light; a micro part such as micro actuator,etc.; a semiconductor device; and the like, and also suitably used forthe semiconductor device and the process for manufacturing the same ofthe present invention described below.

[0164] (Semiconductor Device and Process for Manufacturing aSemiconductor Device)

[0165] The semiconductor device of the present invention is notparticularly limited except having a pattern formed of theabove-described resist pattern of the present invention, and comprisesknown members properly selected according to purposes.

[0166] Concrete examples of the semiconductor device of the presentinvention suitably include flash memory, DRAM, FRAM and the like.

[0167] The semiconductor device of the present invention can be suitablymanufactured according the process for manufacturing a semiconductordevice of the present invention described below.

[0168] The process for manufacturing a semiconductor device of thepresent invention comprises a step for forming a resist pattern to bethickened and a step for patterning, and further comprises otherprocesses properly selected as occasion demands.

[0169] The step for forming a resist pattern comprises a step forforming a resist pattern by applying a resist pattern thickeningmaterial to cover a surface of a resist pattern to be thickened tothicken the resist pattern to be thickened to form the resist pattern,after forming the resist pattern to be thickened on a substrate(underlying layer). Examples of the substrate (the underlying layers)include surface layers for all kinds of members in semiconductordevices, and a substrate such as silicon wafer and surface layer thereofare suitably used. The resist pattern to be thickened is the same asdescribed above. The application process is also the same as describedabove. After the application, the above-mentioned pre-baking,crosslinking baking and the like are preferably performed.

[0170] The step for patterning comprises patterning the substrate(underlying layer) by performing an etching using the resist pattern (asa mask pattern) formed in the step for forming the resist pattern.

[0171] The etching process is not particularly limited, and any processcan be properly selected from known processes according to purposes,suitably including dry etching and the like. The condition of theetching is not particularly limited, and any one can be properlyselected according to purposes.

[0172] Suitable examples of the other processes include a step forapplying surfactant, a step for developing and the like.

[0173] The step for applying surfactant comprises applying thesurfactant to the surface of the resist pattern to be thickened prior tothe step for forming a resist pattern.

[0174] The surfactant can be selected according to the purpose. Theexamples include those same as described above, and more suitably, apolyoxyethylene-polyoxypropylene condensed compound, a polyoxyalkylenealkyl ether compound, a polyoxyethylene alkyl ether compound, apolyoxyethylene derivative compound, a sorbitan fatty acid estercompound, a glycerin fatty acid ester compound, a primary alcoholethoxylate compound, a phenol ethoxylate compound, nonylphenolethoxylatetype, an octylphenolethoxylate type, a lauryl alcohol ethoxylate type,an oleyl alcohol ethoxylate type, a fatty acid ester type, an amidetype, a natural alcohol type, an ethylenediamine type, a secondaryalcohol ethoxylate type, an alkylcationic type, an amide type quaternarycationic type, an ester type quaternary cationic type, an amine oxidetype, a betaine type, and the like.

[0175] The step for developing comprises performing the step fordeveloping of the applied resist pattern thickening material prior tothe step for patterning after the step for forming a resist pattern. Thestep for developing is the same as described above.

[0176] According to the process for manufacturing a semiconductor deviceof the present invention, for example, semiconductor devices of allsorts including flash memory, DRAM, FRAM and the like can be efficientlymanufactured.

EXAMPLE

[0177] Examples of the present invention are more concretely describedbelow, but the present invention is never limited by these examples.

Example 1

[0178] Preparation of Resist Pattern Thickening Material

[0179] Resist pattern thickening materials 1A-1J according to thepresent invention having compositions shown in Table 1 were prepared. InTable 1, the unit of the numeric in parentheses represents a part bymass. In the column of “Resin”, “KW3” represents a polyvinyl acetalresin (manufactured by SEKISUI CHEMICAL Co., Ltd.), and “PVA” shows apolyvinyl alcohol resin (manufactured by KURARAY Co., Ltd, Poval 117).In the column of “Crosslinking agent”, “Uril” representstetramethoxymethyl glycoluril, “Urea” represents N,N′-dimethoxymethyldimethoxyethyleneurea, and “Melamine” representshexamethoxymethylmelamine. In the column of “Surfactant”, “TN-80”represents a non-ionic surfactant (manufactured by ASAHI DENKA Co.,Ltd., a primary alcohol ethoxylate type surfactant), “PC-6” represents anon-ionic surfactant (ASAHI DENKA Co., Ltd., a special phenol ethoxylatetype surfactant), “PC-8” represents a non-ionic surfactant (ASAHI DENKACo., Ltd., a special phenol ethoxylate type surfactant), “PC-12”represents a non-ionic surfactant (ASAHI DENKA Co., Ltd., a specialphenol ethoxylate type surfactant). As the main solvent component exceptthe above resins, crosslinking agents, and compounds which contains acircular structure, a mixture of pure water (deionized water) andisopropyl alcohol (mass ratio of pure water (deionized water) toisopropyl alcohol=98.6:0.4) was used. TABLE 1 Crosslinking Compoundhaving a Resin agent cyclic structure Surfactant 1A KW-3(16) Uril (1.16)Catechin (5) None 1B KW-3(16) Urea (1.16) Catechin (5) None 1C KW-3(16)Melamine Catechin (5) None PVA3 (0.8) 1D KW-3(16) Uril (1.16) Catechin(5) TN-80(0.25) 1E KW-3(16) Urea (1.16) Catechin (5) PC-8(0.25) 1FKW-3(16) Melamine Catechin (5) PC-12(0.25) PVA3 (0.8) 1G KW-3(16) Uril(1.16) Delphinidin (5) None 1H KW-3(16) Uril (1.16) Resorcin(5)TN-80(0.25) 1I KW-3(16) Urea (1.16) 1,3- PC-8(0.25) naphthalene diol (5)1J KW-3(16) Uril (1.16) 4-hydroxyadamantane- PC-6(0.25) 2-carboxylicacid (0.8)

[0180] Resist Pattern and Manufacture Thereof

[0181] Each of the thus-prepared resist pattern thickening materials1A-1J were applied to a hole pattern formed by the ArF resist(manufactured by SUMITOMO CHEMICAL Co., Ltd., PAR700 an alicyclicresist) by spin coating first in a condition of 1000 rpm/5 s and then ina condition of 3500 rpm/40 s, and subjected to pre-baking in a conditionof 85° C./70 s and further to crosslinking baking in a condition of 110°C./70 s. The resulting resist pattern thickening materials 1A-1J werethen rinsed with pure water (deionized water) for 60 sec to remove thenon-crosslinked part, and the resist patterns thickened by the resistpattern thickening materials 1A-1J were developed, whereby the resistpatterns were formed.

[0182] The sizes of the hole patterns formed by the resist patterns (thesizes of the hole patterns formed by the resist patterns afterthickening the resist patterns) were shown in Table 2 as well as theinitial pattern sizes (the sizes of the hole patterns formed by theresist patterns to be thickened). In Table 2, “1A”-“1J” correspond tothe resist pattern thickening materials 1A-1J, respectively. TABLE 2Initial pattern Pattern size after size (nm) thickening (nm) 1A 200.5175.2 1B 203.3 181.2 1C 199.8 180.0 1D 205.7 154.4 1E 202.6 171.7 1F203.9 160.3 1G 198.8 171.1 1H 201.1 148.7 1I 200.8 165.6 1J 202.6 178.6

[0183] Each of the thus-prepared resist pattern thickening materials1A-1J were applied to a line & space pattern formed by the ArF resist(manufactured by SUMITOMO CHEMICAL Co., Ltd., PAR700) by spin coatingfirst in a condition of 1000 rpm/5 s and then in a condition of 3500rpm/40 s, and subjected to pre-baking in a condition of 85° C./70 s andfurther to crosslinking baking in a condition of 110° C./70 s. Theresulting resist pattern thickening materials 1A-1J were then rinsedwith pure water (deionized water) for 60 sec to remove thenon-crosslinked part, and the resist patterns thickened by the resistpattern thickening materials 1A-1J were developed, whereby therespective resist patterns were formed.

[0184] The sizes of the space patterns formed by the resist patterns(the sizes of the space patterns formed by the resist patterns afterthickening the resist patterns) were shown in Table 3 as well as theinitial pattern the sizes (the sizes of the space pattern formed by theresist patterns to be thickened). In Table 3, “1A”-“1J” correspond tothe resist pattern thickening materials 1A-1J, respectively. TABLE 3Initial pattern Pattern space size after space size (nm) thickening (nm)1A 165.2 135.2 1B 162.3 143.8 1C 159.8 137.7 1D 155.7 116.9 1E 158.5128.8 1F 160.2 123.0 1G 163.4 125.4 1H 160.0 121.1 1I 158.0 120.5 1J163.8 138.1

[0185] It is apparent from the results of Tables 2 and 3 that the resistpattern thickening material of the present invention is applicable toboth a hole pattern and a line & space pattern to thicken them. Theresist pattern thickening material of the present invention can make theinside diameter of the hole pattern narrow and fine when used for theformation of the hole pattern, make the width of a linear pattern (thespace between resist patterns forming the linear pattern) small and finewhen used for the formation of the linear pattern, and increase the areaof an isolated pattern when used for the formation of the isolatedpattern.

[0186] The resist pattern thickening materials 1D, 1H, 1I and 1J of thepresent invention were applied and crosslinked onto the surface of aresist formed on a silicon substrate to form surface layers 0.5 μm thickthereon, respectively. These surface layers and the KrF resist(manufactured by SHIPLEY, UV-6) and a polymethyl methacrylate (PMMA) forcomparison were etched for 3 minutes by use of an etching machine(Parallel-plate type RIE device, manufactured by FUJITSU LIMITED) underconditions of Pμ=200 W, pressure=0.02 Torr, CF₄ gas=100 sccm, and thefilm reduction amounts of samples were measured to calculate the etchingrates, which were then relatively evaluated on the basis of the etchingrate of the KrF resist. TABLE 4 Material Rate name Etching rate (nm/s)ratio UV-6 62.7 (627 Å/s) 1.00 PMMA 77.0 (770 Å/s) 1.23 1D 60.0 (600Å/s) 0.96 1H 61.0 (610 Å/s) 0.97 1I 59.0 (590 Å/s) 0.94 1J 57.5 (575Å/s) 0.92

[0187] It is apparent from the result of Table 4 that the etchingresistances of the resist pattern thickening materials of the presentinvention are close to the KrF resist and more remarkably excellent thanthe PMMA.

[0188] When the resist pattern thickening materials 1A-1J were appliedonto the resist pattern to be thickened on a wafer substrate allowed tostand out of a clean room for 1 month after exposure, the similarpattern thickening effect as in the immediate application after exposurecan be obtained.

[0189] It is supposed from this result that the resist patternthickening material of the present invention thickens the resist patternto be thickened not by using a crosslinking reaction by diffusion ofacid as the prior art called RELACS, but depending on the compatibilitywith the resist pattern to be thickened.

Example 2

[0190] Preparation of Resist Pattern Thickening Material

[0191] Resist pattern thickening materials 2A-2M according to thepresent invention having compositions shown in Table 5 were prepared. InTable 5, the unit of the numeric in parentheses represents a part bymass. In the column of “Resin”, “Resin 1”, “Resin 2” and “Resin 3” aresynthesized as shown hereinafter. In the column of “Crosslinking agent,”“Uril” represents tetramethoxymethyl glycoluril, “Urea” representsN,N′-dimethoxymethyl dimethoxyethyleneurea, and “Melamine” representshexamethoxymethylmelamine. In the column of “Surfactant”, “TN-80”represents a non-ionic surfactant (manufactured by ASAHI DENKA Co.,Ltd., a primary alcohol ethoxylate type surfactant). As the main solventcomponent except the above resins, crosslinking agents, and surfactantagents and a mixture of pure water (deionized water) and isopropylalcohol (mass ratio of pure water (deionized water) to isopropylalcohol=16:0.75) was used. “Resin 1” is a Polyvinyl β-resorcin acetalresin synthesized as shown hereinafter. Namely, 10 g of PVA 500(manufactured by KANTO KAGAKU) was dissolved in 100 g of deionizedwater, 0.8 g of concentrated hydrochloride was added in the deionizedwater, and then the deionized water was stirred at the temperature of40° C. for three hours. 2.36 g of β-resorcin aldehyde (manufactured byTOKYO KASEI KOGYO Co., Ltd.) was further added to the deionized water,and the deionized water was then stirred at the temperature of 40° C.for six hours. After the temperature of the reacted solution wasdecreased to room temperature, 15 mass % of THAM(tetramethylammoniumhydroxide) was added to the deionized water toneutralize. The reacted solution was dripped into 2 L ethanol toseparate the resins from the reacted solution. The resins were filteredwith a glass filter and were dried at 45° C. under reduced pressure invacuum baking oven for six hours. After repeating this process threetimes, an aimed polyvinyl β-resorcin acetal resin was synthesized. Theyield was 6.8 g. The ratio of acetalization by NMR was 20.6 mol %.

[0192] “Resin 2” is “Polyvinyl-2,3-dihydroxybenz acetal resin”synthesized as shown hereinafter. Namely, 3,4-dihydroxybenz acetal resinwas synthesized by the same processes of “Resin 1” except replacingβ-resorcin aldehyde with 2,3-dihydroxybenz aldehyde. The yield was 6.6g. The ratio of acetalization by NMR was 20.1 mol %.

[0193] “Resin 3” is “polyvinyl β-resorcin acetal resin” synthesized asshown hereinafter. Namely, 10 g of polyvinyl alcohol 500 (manufacturedby KANTO KAGAKU) was dissolved in 100 g of deionized water, 0.4 g ofconcentrated hydrochloride was added in the deionized water, and thenthe deionized water was stirred at the temperature of 40° C. for threehours. 0.5 g of β-resorcin aldehyde (manufactured by TOKYO KASEI KOGYOCo., Ltd.) was added to the deionized water, and the deionized water wasthen stirred at the temperature of 40° C. for six hours. The temperatureof the reacted solution was decreased to ambient temperature, 15 mass %of THAM (tetramethyllead ammonium hydro oxide) was added to thedeionized water to neutralize. The reacted solution was dripped into 2 Lethanol to separate the resins from the reacted solution. The resinswere filtered with a glass filter and were then dried under reducedpressure in a vacuum baking oven of 45° C. for six hours. Afterrepeating this process three times, an aimed polyvinyl β-resorcin acetalresin was synthesized. The yield was 4.1 g. The ratio of acetalizationby NMR was 3.7 mol %. TABLE 5 Lubricating material Crosslinking nameResin agent Surfactant agent 2A Resin 1 (1) Uril (0.5) None 2B Resin 1(1) Urea (0.5) None 2C Resin 1 (1) Melamine (0.25) None 2D Resin 1 (1)Uril (0.5) TN-80(0.0025) 2E Resin 1 (1) Urea (0.5) TN-80(0.0025) 2FResin 1 (1) Melamine (0.25) TN-80(0.0025) 2G Resin 2 (1) Uril (0.5) None2H Resin 2 (1) Urea (0.5) None 2I Resin 2 (1) Melamine (0.25) None 2JResin 2 (1) Uril (0.5) TN-80(0.0025) 2K Resin 2 (1) Urea (0.5)TN-80(0.0025) 2L Resin 2 (1) Melamine (0.25) TN-80(0.0025) 2M Resin 3(1) Uril (0.5) None

[0194] Resist Pattern and Manufacture Thereof

[0195] Each of the thus-prepared resist pattern thickening materials 2Ato 2L were applied to a hole pattern formed of the ArF resist(manufactured by SUMITOMO CHEMICAL Co., Ltd., PAR700 an alicyclicresist) by spin coating first in a condition of 1000 rpm/5 s and then ina condition of 3500 rpm/40 s, and subjected to pre-baking in a conditionof 85° C./70 s and further to crosslinking baking in a condition of 110°C./70 s. The resulting resist pattern thickening materials 2A to 2L werethen rinsed with pure water (deionized water) for 60 seconds to removethe non-crosslinked part, and the resist patterns thickened by theresist pattern thickening materials 2A to 2L were developed, whereby theresist patterns were formed.

[0196] The sizes of the patterns formed by the formed resist patterns(resist patterns) were shown in Table 6 as well as the initial patternsizes (the sizes of the hole patterns before thickening the resistpatterns). In Table 6, “2A” to “2L” correspond to the resist patternthickening materials 2A to 2L, respectively. TABLE 6 Pattern size afterLubricating Initial pattern lubricating material name size (nm) (nm) 2A201.5 194.2 2B 203.1 197.4 2C 199.8 190.9 2D 205.1 191.8 2E 195.6 187.42F 196.9 170.3 2G 198.0 190.0 2H 201.0 194.8 2I 200.6 189.6 2J 199.8184.6 2K 204.1 191.0 2L 200.8 173.9

[0197] Each of the thus-prepared resist pattern thickening materials2A-2L were applied onto a line & space pattern formed of the ArF resist(manufactured by SUMITOMO CHEMICAL Co., Ltd., PAR700 an alicyclicresist) by spin coating first in a condition of 1000 rpm/5 s and then ina condition of 3500 rpm/40 s, and were subjected to pre-baking in acondition of 85° C./70 s and further to crosslinking baking in acondition of 110° C./70 s. The resulting resist pattern thickeningmaterials 2A-2L were then rinsed with pure water (deionized water) for60 seconds to remove the non-crosslinked part, and the resist patternsthickened by the resist pattern thickening materials 2A-2L weredeveloped, whereby the respective resist patterns were formed.

[0198] The sizes of the patterns formed by the resist patterns wereshown in Table 7 as well as the initial pattern sizes (the sizes of theline & space patterns before thickening the resist patterns). In Table7, “2A”-“2L” correspond to the resist pattern thickening materials2A-2L, respectively. TABLE 7 Lubricating Initial pattern material spacesize Pattern space size name (nm) after lubricating (nm) 2A 160.2 147.22B 158.8 148.5 2C 159.6 147.2 2D 157.7 128.6 2E 160.5 139.8 2F 161.2129.4 2G 160.4 140.1 2H 163.0 145.2 2I 156.8 136.5 2J 162.1 129.4 2K161.8 131.8 2L 155.6 123.9

[0199] It is apparent from the results of Tables 6 and 7 that the resistpattern thickening material of the present invention is applicable toboth a hole pattern and a line & space pattern to thicken them. Theresist pattern thickening material of the present invention can make theinside diameter of the hole pattern narrow and fine when used for theformation of the hole pattern, make the pitch of a linear pattern (thespace between resist patterns forming the linear pattern) small and finewhen used for the formation of the linear pattern, and increase the areaof an isolated pattern when used for the formation of the isolatedpattern.

[0200] The resist pattern thickening materials 2A, 2G and 2M of thepresent invention were applied and crosslinked onto the surface of aresist formed on a silicon substrate to form surface layers 0.5 μm thickthereon, respectively. These surface layers and the KrF resist(manufactured by SHIPLEY, UV-6) and a polymethyl methacrylate (PMMA) forcomparison were etched for 3 minutes by use of an etching machine(Parallel-plate type RIE device, manufactured by FUJITSU LIMITED) underconditions of Pμ=200 W, pressure=0.02 Torr, CF₄ gas=100 sccm, and thefilm reduction amounts of samples were measured to calculate the etchingrates, which were then relatively evaluated on the basis of the etchingrate of the KrF resist. TABLE 8 Material name Etching rate (nm/s) Rateratio UV-6 63.3 (633 Å/s) 1.00 PMMA 78.1 (781 Å/s) 1.23 2A 59.5 (595Å/s) 0.94 2G 60.0 (600 Å/s) 0.95 2M 80.5 (805 Å/s) 1.27

[0201] It is apparent from the result of Table 8 that the etchingresistance of the resist pattern thickening materials of the presentinvention is close to the KrF resist and more remarkably excellent thanthe PMMA.

[0202] The arylacetal content of the resist pattern thickening material2M is less than 5 mol %. The etching resistances for the resist patternthickening material 2M is slightly inferior to those of the resistpattern thickening materials 2A and G, both of which has an arylacetalcontent of 5 mol % or more.

[0203] When the resist pattern thickening materials 2A-2M were appliedonto the resist pattern to be thickened on a wafer substrate allowed tostand out of a clean room for 1 month after exposure, the same patternthickening effect as in the immediate application of the resist patternthickening material after exposure can be obtained.

[0204] It is assumed from this result that the resist pattern thickeningmaterial of the present invention thickens the resist pattern not by useof a crosslinking reaction by diffusion of acid as the conventionaltechnique called RELACS, but depending on the compatibility with theresist pattern.

Example 3

[0205] Flash Memory and its Manufacture

[0206] Example 3 is one embodiment of the semiconductor device andmanufacturing process thereof of the present invention using the resistpattern thickening material of the present invention. In Example 3,resist films 26, 27, 29, 32 and 34 are thickened by use of the resistpattern thickening material of the present invention according to thesame process as in Examples 1 and 2.

[0207]FIGS. 3A and 3B are upper surface views (plan views) of a FLASHEPROM called FLOTOX type or ETOX type. FIGS. 4A to 4C, FIGS. 5D to 5F,and FIGS. 6G to 6I are schematic sectional views for showing one examplefor the manufacturing process for the FLASH EPROM, wherein the leftviews in FIGS. 4A through 6I are schematic sectional (A-directionalsectional) views in the gate lateral direction (X-direction in FIGS. 3Aand 3B) of the part for forming a MOS transistor having a floating gateelectrode in a memory cell pat (first element region), the central viewsare schematic sectional (B-directional sectional) views in the gatelongitudinal direction (Y-direction in FIGS. 3A and 3B) orthogonal tothe X-direction in the memory cell part of the same part as in the leftviews, and the right views are schematic sectional (A-directionalsectional in FIGS. 3A and 3B) views of the part for forming a MOStransistor in a peripheral circuit part (second element region).

[0208] A field oxide film 23 by SiO₂ film was selectively formed on theelement separating region on a p-type Si substrate 22 as shown in FIG.4A. Thereafter, a first gate insulation film 24 a in the MOS transistorof the memory cell part (first element region) was formed with SiO₂ filmby thermal oxidation so as to have a thickness of 10 nm to 30 nm (100 Åto 300 Å), and a second gate insulation film 24 b in the MOS transistorof the peripheral circuit part (second element region) was also formedwith SiO₂ film by thermal oxidation so as to have a thickness of 10 nmto 50 nm (100 Å to 500 Å) in another process. When the first gateinsulation film 24 a and the second gate insulation film 24 b are formedin the same thickness, the oxide films may be formed simultaneously inthe same process.

[0209] In order to form the MOS transistor having a n-depression typechannel in the memory cell part (the left and central views in FIG. 4A),the peripheral circuit part (the right view in FIG. 4A) was masked witha resist film 26 for the purpose of controlling threshold voltage. Tothe region for forming a channel region just under the floating gateelectrode, phosphor (P) or arsenic (As) was introduced as n-typeimpurity in a dose of 1×10¹¹-1×10¹⁴ cm⁻² by ion implantation to form afirst threshold control layer 25 a. The dose and conductive type of theimpurity can be properly selected depending on selection of depressiontype or accumulation type.

[0210] In order to form the MOS transistor having a n-depression typechannel in the peripheral circuit part (the right view of FIG. 4B), thememory cell part (the left and central views in FIG. 4B) was masked witha resist film 27 for the purpose of controlling the threshold voltage.To the region for forming a channel region just under the gateelectrode, phosphor (P) or arsenic (As) was introduced as n-typeimpurity in a dose of 1×10¹¹-1×10¹⁴ cm⁻² by ion implantation to form asecond threshold control layer 25 b.

[0211] A first polysilicon film (first conductor film) 28, 50 nm to 200nm (500 Å to 2000 Å)-thick, was formed on the whole surface as thefloating gate electrode of the MOS transistor of the memory cell part(the left and central views in FIG. 4C) and the gate electrode of theMOS transistor of the peripheral circuit part (the right view in FIG.4C).

[0212] The first polysilicon film 28 was patterned with a resist film 29formed as a mask, as shown in FIG. 5D, to form a floating gate electrode28 a in the MOS transistor of the memory cell part (the left and centralviews in FIG. 5D). At this time, the patterning was performed inX-direction so as to have a final dimension width, as shown in FIG. 5D,but not in Y-direction to leave the region for forming a S/D regionlayer as covered with the resist film 29.

[0213] After the resist film 29 was removed as shown in the left andcentral views in FIG. 5E, a capacitor insulation film 30 a comprisingSiO₂ film was formed in a thickness of about 20 nm to 50 nm (200 Å to500 Å) by thermal oxidation so as to cover the floating gate electrode28 a. At this time, a capacitor insulating film 30 b comprising SiO₂film is also formed on the first polysilicon film 28 of the peripheralcircuit part (the right view in FIG. 5E). The capacitor insulation films30 a and 30 b, which were formed of only SiO₂ films herein, may beformed of a composite film comprising SiO₂ film and Si₃N₄ film laminatedin 2-3 layers.

[0214] A second polysilicon film (second conductor film) 31 forming acontrol gate electrode was formed in a thickness of 50 nm to 200 nm (500Å to 2000 Å), as shown in FIG. 5E, so as to cover the floating gateelectrode 28 a and the capacitor insulation film 30 a.

[0215] The memory cell part (the left and central views in FIG. 5F) wasmasked with a resist film 32 as shown in FIG. 5F, and the secondpolysilicon film 31 and capacitor insulation film 30 b of the peripheralcircuit part (the right view in FIG. 5F) were successively removed byetching to expose the first polysilicon film 28.

[0216] The second polysilicon film 31, capacitor insulation film 30 aand first polysilicon film 28 a patterned only in X-direction of thememory cell part (the left and central views in FIG. 6G) were patternedin Y-direction with the resist film 32 as a mask so as to have the finaldimension of a first gate part 33a as shown in FIG. 6G), whereby alamination by a control gate electrode 31 a/a capacitor insulation film30 c/a floating gate electrode 28 c about 1 μm in width was formed inY-direction. The first polysilicon film 28 of the peripheral circuitpart (the right view in FIG. 6G) was also patterned with the resist film32 as a mask so as to have the final dimension of a second gate part 33b, whereby a gate electrode 28 b about 1 μm in width was formed.

[0217] By use of the lamination by the control gate electrode 31 a/thecapacitor insulation film 30 c/the floating gate electrode 28 c of thememory cell part (the left and central views in FIG. 6H) as mask,phosphor (P) or arsenic (As) was introduced to the Si substrate 22 inthe element forming region in a dose of 1×10¹⁴-1×10¹⁶ cm⁻² by ionplantation to form n-type S/D region layers 35 a and 35 b. Further, byuse of the gate electrode 28 b of the peripheral circuit part (the rightview in FIG. 6H) as mask, phosphor (P) or arsenic (As) was introduced asn-type impurity in a dose of 1×10¹⁴-1×10¹⁶ cm⁻² to the Si substrate 22in the element forming region to form S/D region layers 36 a and 36 b.

[0218] An innerlayer insulation film 37 by PSG film was formed in athickness of about 500 nm (5000 Å) so as to cover the first gate part 33a of the memory cell part (the left and central views in FIG. 6I) andthe second gate part 33 b of the peripheral circuit part (the right viewin FIG. 6I).

[0219] Thereafter, contact holes 38 a and 38 b and contact holes 39 aand 39 b were formed in the innerlayer insulating film 37 formed on theS/D region layers 35 a and 35 b and the S/D region layers 36 a and 36 b,and S/D electrodes 40 a and 40 b and S/D electrodes 41 a and 41 b werethen formed.

[0220] According to the above, a FLASH EPROM was manufactured assemiconductor device as shown in FIG. 6I.

[0221] In this FLASH EPROM, since the second gate insulating film 24 bof the peripheral circuit part (the right views in FIGS. 4A through 5F)are always covered with the first polysilicon film 28 or gate electrode28 b after the formation (the right views in FIGS. 4C to 5F), the secondgate insulating film 24 b keeps the originally formed thickness.Therefore, the thickness control of the second gate insulating film 24 bcan be facilitated, and the adjustment of conductive impurityconcentration for the control of threshold voltage can be alsofacilitated.

[0222] In the above example, the patterning for the formation of thefirst gate part 33 a is performed with a prescribed width first in thegate lateral direction (X-direction in FIGS. 3A and 3B) and then in thegate longitudinal direction (Y-direction in FIGS. 3A and 3B) to form afinal prescribed width, but the patterning may be reversely performedwith the prescribed width first in the gate longitudinal direction(Y-direction in FIGS. 3A and 3B) and then in the gate lateral direction(X-direction in FIGS. 3A and 3B) to form the final prescribed width.

[0223] The example of manufacture of FLASH EPROM shown in FIGS. 7Athrough 7C is the same as the above example except changing thefollowing process after the process shown in FIG. 5F in the aboveembodiment as shown in FIGS. 7A through 7C. Namely, the different pointfrom the above example is that a high melting point metallic membrane(fourth conductor film) 42 comprising tungsten (W) film or titanium (Ti)film was formed in a thickness of about 200 nm (2000 Å) on the secondpolysilicon film 31 of the memory cell part (the left and central viewsin FIG. 7A) and the first polysilicon film 28 of the peripheral circuitpart (the right view in FIG. 7A to provide a polycide film. Theprocesses after FIG. 7A or the processes shown in FIGS. 7B through 7Cwere performed in the same manner as in FIGS. 6G through 6I. Thedescription for the same process as FIGS. 6G through 6I was omitted, andthe same part as in FIGS. 6G through 6I was shown by the same referencemark in FIGS. 7A through 7C.

[0224] According to the above, a FLASH EPROM was manufactured assemiconductor device as shown in FIG. 7C.

[0225] In this FLASH EPROM, since the high melting point metallicmembranes (fourth conductor films) 42 a and 42 b are provided on thecontrol gate electrode 31 a and the gate electrode 28 b, the electricresistance can be further reduced.

[0226] As the high melting point metallic membrane (fourth conductorfilm), a high melting point metal silicide membrane such as titaniumsilicide (TiSi) membrane, etc. may be used in addition to theabove-mentioned high melting point metallic membranes (fourth conductorfilms) 42 a and 42 b.

[0227] The example of manufacturing FLASH EPROM shown in FIGS. 7Athrough 7C is the same as the above example except constituting thesecond gate part 33 c of the peripheral circuit part (second elementregion) (the right view in FIG. 8A) to have a structure comprising afirst polysilicon film 28 b (first conductor film)/a SiO₂ film 30 d(capacitor insulation film)/a second polysilicon film 31 b (secondconductor film) similarly to the first gate part 33 a of the memory cellpart (first element region) (the left and central views in FIG. 8A), andshort-circuiting the first polysilicon film 28 b and the secondpolysilicon film 31 b to form a gate electrode as shown in FIG. 8B orFIG. 8C.

[0228] As shown in FIG. 8B, an opening part 52 a extending through thefirst polysilicon film 28 b (first conductor film)/the SiO₂ film 30 d(capacitor insulation film)/the second polysilicon film 31 b (the secondconductor film) is formed, for example, in a position different from thesecond gate part 33 c shown in FIG. 8A, e.g., on an insulation film 54,and a third conductor film, for example, a high melting point metallicmembrane 53 a such as W film, Ti film, etc. is buried in the openingpart 52 a, whereby the first polysilicon film 28 b and the secondpolysilicon film 31 b are short-circuited. As shown in FIG. 8C, anopening part 52 b extending through the first polysilicon film 28 b(first conductor film)/the SiO₂ film 30 d (capacitor insulation film) isformed to expose the first polysilicon film 28 b of the lower layer tothe bottom of the opening part 52 b, and a third conductor film, forexample, a high melting point metallic membrane 53 b such as W film, Tifilm, etc. is buried in the opening part 52 b, whereby the firstpolysilicon film 28 b and the second polysilicon film 31 b areshort-circuited.

[0229] In this FLASH EPROM, since the second gate part 33 c of theperipheral circuit part has the same structure as the first gate part 33a of the memory cell part, the peripheral circuit part can be formedsimultaneously with the formation of the memory cell part to effectivelysimplify the manufacturing process.

[0230] The third conductor film 53 a or 53 b and the high melting pointmetallic membrane (fourth conductor film) 42 may be simultaneouslyformed as a common high melting point metallic membrane in addition tothe above independent formation.

Example 4

[0231] Manufacture of Magnetic Head

[0232] Example 4 relates to the manufacture of a magnetic head as anapplied example of the resist pattern according to the present inventionusing the resist pattern thickening material according to the presentinvention. In Example 4, resist patterns 102 and 126 are thickened bythe same process as in Example 1 and 2 by use of the resist patternthickening material according to the present invention.

[0233]FIGS. 9A through 9D are flowcharts for showing the manufacture ofthe magnetic head.

[0234] A resist film was formed on an innerlayer insulation layer 100 ina thickness of 6 μm, as shown in FIG. 9A, followed by exposure anddevelopment to form a resist pattern to be thickened 102 having anopening pattern for forming a spiral thin film magnetic coil.

[0235] A plating underlying layer 106 comprising the lamination of a Tiadhesion layer 0.01 μm thick and a Cu adhesion layer 0.05 μm thick wasformed by evaporation, as shown in FIG. 9B, on the resist pattern to bethickened 102 and the part having no resist pattern to be thickened 102formed thereon or the exposed surface of the opening part 104 on theinnerlayer insulation layer 100.

[0236] A thin film conductor 108 comprising a Cu plating film 3 μm thickwas formed, as shown in FIG. 9C, in the part having no resist pattern tobe thickened 102 formed thereon, or on the surface of the platingunderlying layer 106 formed on the exposed surface of the opening part104 on the innerlayer insulation layer 100.

[0237] When the resist pattern to be thickened 102 is dissolved andremoved and lifted off from the innerlayer insulation layer 100 as shownin FIG. 9D, a thin film magnetic coil 110 by the spiral pattern of thethin film conductor 108 is formed.

[0238] According to the above, the magnetic head was manufactured.

[0239] In the resulting magnetic head, since a spiral pattern is finelyformed by the resist pattern to be thickened 102 thickened by use of thethickening material according to the present invention, the thin filmmagnetic coil 110 is fine and fine, and also excellent inmass-productivity.

[0240]FIGS. 10 through 15 are flowcharts for showing the manufacture ofanother magnetic head.

[0241] A gap layer 114 was formed on a ceramic nonmagnetic substrate 112by sputtering as shown in FIG. 10. An insulator layer by silicon oxideand a conductive underlying layer comprising Ni—Fe permalloyperm alloy,which are not shown, are preliminarily formed on the nonmagneticsubstrate 112 by sputtering, and a lower magnetic layer comprising Ni—Fepermalloyperm alloy is further formed thereon. A resin insulation film116 was formed by use of a thermosetting resin in a prescribed region onthe gap layer 114 except the part forming the magnetic tip of the lowermagnetic layer not shown. A resist material was then applied to theresin insulation film 116 to form a resist film 118.

[0242] The resist film 118 was then subjected to exposure anddevelopment, as shown in FIG. 11, to form a spiral pattern. The resistfilm 118 of the spiral pattern was thermally set at several hundreds °C. for about 1 hr as shown in FIG. 12 to form a projection-like firstspiral pattern 120. A conductive underlying layer 122 comprising Cu wasfurther formed on the surface thereof so as to cover it.

[0243] A resist material was applied onto the conductive underlyinglayer 122 by spin coating to form a resist film 124, as shown in FIG.13, and the resist film 124 was patterned on the first spiral pattern120 to form a resist pattern 126.

[0244] A Cu conductor layer 128 is formed by plating, as shown in FIG.14, on the exposed surface of the conductive underlying layer 122, or onthe part having no resist pattern 126 formed thereon. Thereafter, theresist pattern 126 was lifted off, as shown in FIG. 15, from theconductive underlying layer 122 by being dissolved and removed to form aspiral thin film magnetic coil 130 by the Cu conductor layer 128.

[0245] According to the above, a magnetic head having the magnetic layer132 on the resin insulation film 116 and the thin film magnetic coil 130on the surface, as shown in the plan view of FIG. 16, was manufactured.

[0246] In the resulting magnetic head, since a spiral pattern is finelyformed by the resist pattern 126 thickened by use of the thickeningmaterial according to the present invention formed thereon, the thinfilm magnetic coil 130 is fine and fine, and also excellent inmass-productivity.

[0247] According to the present invention, it is possible to provide aresist pattern thickening material useful for forming a fine patternwith low cost by applying the resist pattern thickening material,exceeding an exposure limit for an optical resource of an exposuredevice, improving the etching resistance of the resist pattern.

[0248] Further, according to the present inventions, it is possible toprovide a resist pattern which can be patterned by using ArF excimerlaser, has a fine structure, and is excellent in etching resistance.

[0249] According to the present invention, it is also possible toprovide a process for forming a resist pattern capable of using ArFexcimer laser light as exposure light with excellent mass-productivityand forming a fine pattern by resist pattern over the exposure limit oflight with low cost, with ease, and with improving etching resistance.

[0250] According to the present invention, it is possible to provide ahigh-performance semiconductor device having a fine pattern formed by aresist pattern.

[0251] According to the present invention, it is possible to provide ahigh-performance semiconductor device having a fine pattern formed by aresist pattern.

[0252] Further more, according to the present invention, it is possibleto use the ArF excimer laser light as an exposure light and is alsopossible to provide an efficient and mass productive process formanufacturing a high-performance semiconductor device having a finepattern.

What is claimed is:
 1. A resist pattern thickening material comprising;a resin; a crosslinking agent; and a compound having a cyclic structure.2. A resist pattern thickening material according to claim 1, whereinthe resist pattern thickening material is one of a water-soluble and analkali-soluble.
 3. A resist pattern thickening material according toclaim 1, wherein the compound having a cyclic structure exhibits one ofa water-solubility of 1 g or more to 100 g of 25° C. water, and analkali-solubility 100 g of 2.38% by mass of 25° C.tetramethylammoniumhydroxide aqueous solution.
 4. A resist patternthickening material according to claim 1, wherein the compound having acyclic structure has two or more of polar groups.
 5. A resist patternthickening material according to claim 4, wherein the polar groups areselected from a hydroxyl group, an amino group, a sulfonyl group, acarboxyl group, a carbonyl group, and derivatives thereof.
 6. A resistpattern thickening material according to claim 1, wherein the compoundhaving a cyclic structure is selected from an aromatic compound, analicyclic compound, and a heterocyclic compound.
 7. A resist patternthickening material according to claim 6, wherein the aromatic compoundis selected from a polyphenol compound, an aromatic carboxylic acidcompound, a naphthalene polyvalent alcohol compound, a benzophenonecompound, a flavonoid compound, and derivatives and glycosides thereof,the alicyclic compound is selected from polycycloalkane, cycloalkane,steroids, derivatives and glycosides thereof, and the heterocycliccompound is selected from pyrrolidine, pyridine, imidazole, oxazole,morpholine, pyrrolidone, furan, pyran, saccharides and derivativesthereof.
 8. A resist pattern thickening material according to claim 1,wherein the resin has a cyclic structure at a part of the resin.
 9. Aresist pattern thickening material comprising: a resin which has acyclic structure at a part of the resin; and a crosslinking agent.
 10. Aresist pattern thickening material according to claim 8, wherein thecyclic structure is selected from an aromatic compound, an alicycliccompound, and a heterocyclic compound.
 11. A resist pattern thickeningmaterial according to claim 8, wherein the resin which has a cyclicstructure at a part of the resin has a content of 5 mol % or more.
 12. Aresist pattern thickening material according to claim 1, wherein theresin has one of a water-solubility and an alkali-solubility.
 13. Aresist pattern thickening material according to claim 1, wherein theresin is one selected at least from polyvinyl alcohol, polyvinyl acetal,and polyvinyl acetate.
 14. A resist pattern thickening materialaccording to claim 1, wherein the resin contains 5% by mass to 40% bymass of the polyvinyl acetal.
 15. A resist pattern thickening materialaccording to claim 1, wherein the resin has two or more of polar groups.16. A resist pattern thickening material according to claim 15, whereinthe polar groups are selected from a hydroxyl group, an amino group, asulfonyl group, a carboxyl group, a carbonyl group, and derivativesthereof.
 17. A resist pattern thickening material according to claim 1,wherein the crosslinking agent is one selected at least from a melaminederivative, a urea derivative and a uril derivative.
 18. A resistpattern thickening material according to claim 1 further comprising asurfactant.
 19. A resist pattern thickening material according to claim1, wherein the surfactant is one type selected at least from a non-ionicsurfactant, a cationic surfactant, an anionic surfactant, and anampholytic surfactant.
 20. A resist pattern thickening materialaccording to claim 19, wherein the non-ionic surfactant is one selectedat least from a polyoxyethylene-polyoxypropylene condensed compound, apolyoxyalkylene alkyl ether compound, a polyoxyethylene alkyl ethercompound, a polyoxyethylene derivative compound, a sorbitan fatty acidester compound, a glycerin fatty acid ester compound, a primary alcoholethoxylate compound, a phenol ethoxylate compound, an alkoxylatesurfactant, a fatty acid ester surfactant, an amide surfactant, alcoholsurfactant, and an ethylenediamine surfactant; the cationic surfactantis one selected at least from an alkyl cationic surfactant, an amidetype quaternary cationic surfactant, and an ester type quaternarycationic surfactant; and the ampholytic surfactant is one selected atleast from an amine oxide surfactant, and a betaine surfactant.
 21. Aresist pattern thickening material according to claim 1, furthercomprising an organic solvent.
 22. A resist pattern thickening materialaccording to claim 21, wherein the organic solvent is one selected atleast from an alcohol solvent, a chain ester solvent, a cyclic estersolvent, a ketone solvent, a chain ether solvent, and a cyclic ethersolvent.
 23. A resist pattern comprising a surface layer provided on aresist pattern to be thickened, with an etching rate (nm/s) ratio(resist pattern to be thickened/surface layer) of 1.1 or more under thesame condition; and the etching rate (nm/s) ratio (resist pattern to bethickened/surface layer) is an etching rate (nm/s) ratio of the resistpattern to be thickened to the surface layer.
 24. A resist patternaccording to claim 23, wherein the surface layer has a compound having acyclic structure.
 25. A resist pattern according to claim 23, wherein acontent of the compound having a cyclic structure is gradually reducedfrom the surface layer to an inner part.
 26. A resist pattern accordingto claim 23, wherein a surface of the resist pattern to be thickened isapplied with a resist pattern thickening material comprising: a resin; acrosslinking agent; and a compound having a cyclic structure so as tocover the surface of the resist pattern to be thickened after formingthe resist pattern to be thickened.
 27. A process for forming a resistpattern comprising: a step for applying a resist pattern thickeningmaterial so as to cover a surface of a resist pattern to be thickenedafter forming the resist pattern to be thickened, wherein the resistpattern thickening material comprises: a resin; a crosslinking agent;and a compound having a cyclic structure.
 28. A process for forming aresist pattern according to claim 27, wherein a development of theresist pattern thickening material is performed after applying theresist pattern thickening material.
 29. A process for forming a resistpattern according to claim 28, wherein the development is performed byusing deionized water.
 30. A process for forming a resist patternaccording to claim 27, wherein the resist pattern has a surface layerprovided on a resist pattern to be thickened, with an etching rate(nm/s) ratio (resist pattern to be thickened/surface layer) of 1.1 ormore under the same condition; and the etching rate (nm/s) ratio (resistpattern to be thickened/surface layer) is an etching rate (nm/s) ratioof the resist pattern to be thickened to the surface layer.
 31. Aprocess for forming a resist pattern according to claim 30, wherein thesurface layer has at least one of a cyclic structure and a compoundhaving a cyclic structure.
 32. A process for forming a resist patternaccording to claim 30, wherein a content of one of the cyclic structureand a compound having a cyclic structure is gradually reduced from thesurface layer to an inner part.
 33. A semiconductor device comprising apattern formed by a resist pattern, wherein the resist pattern comprisesa surface layer on the resist pattern to be thickened, and the surfacelayer provided on the resist pattern to be thickened, with an etchingrate (nm/s) ratio of 1.1 or more of (resist pattern to bethickened/surface layer) of the resist pattern to the surface layerunder the same condition.
 34. A process for manufacturing asemiconductor device comprising the steps of: forming a resist patternby applying a resist pattern thickening material to cover a surface of aresist pattern to be thickened to thicken the resist pattern to bethickened to form the resist pattern, after forming the resist patternto be thickened on an underlying layer; and patterning the underlyinglayer by performing an etching using the resist pattern formed in thestep for forming the resist pattern which is thickened as a mask,wherein the resist pattern thickening material comprises a resin, across-linking agent, and a compound having a cyclic structure.
 35. Aprocess for manufacturing a semiconductor device according to claim 34,wherein the resist pattern is formed of an ArF resist.
 36. A process formanufacturing a semiconductor device according to claim 35, wherein theArF resist is one type selected at least from an acryl resist having aside-chain of an alicyclic group, a cycloolefin-maleic acid anhydrideresist, and a cycloolefin resist.
 37. A process for manufacturing asemiconductor device according to claim 34, further comprising: a stepfor applying a non-ionic surfactant to the surface of the resist patternto be thickened prior to the step for forming the resist pattern;wherein the non-ionic surfactant is one selected at least from apolyoxyethylene-polyoxypropylene condensed compound, a polyoxyalkylenealkyl ether compound, a polyoxyethylene alkyl ether compound, apolyoxyethylene derivative compound, a sorbitan fatty acid estercompound, a glycerin fatty acid ester compound, a primary alcoholethoxylate compound, and a phenol ethoxylate compound.